Ankit Gopani is Lead Design Verification Engineer at SmartPlay Inc, USA. Ankit has been in the industry for more than 9 years. He pursued Diploma in E.C, B.E in Electronics and Communication and MBA in software project management.
“Class” – The Classical feature !!
October 31st, 2013 by Ankit Gopani
Let’s understand the classical feature of System Verilog ‘Class‘. Here I would try to explain on class feature, object properties and methods, object instantiation, class methods polymorphism and constructor concept.
What is class and why is it classical 🙂 Lets understand
- Class is a generalization of the data type concept and central to the Object Oriented Programming.
- A class is a type that includes data and subroutines like functions and tasks.
- The class properties and methods creates a capabilities of some kind of objects.
Usage of class with example:
class AsicWithAnkit ;
//Data of class properties
bit [3:0] cmd ;
bit [7:0] addr;
function new ();
cmd = 3’b000;
addr = 8’h00;
function display ();
$display (“Command =%h”, cmd );
$display (“Addresss =%h,” addr);
endfunction : display
task clean ();
cmd = ‘h0;
addr = ‘h0;
endtask : clean
endclass : AsicWithAnkit
Above example gives an idea on how to declare a class and their properties, usage of those properties by instantiating class object is the next step to use properties defined inside class body.
Lets understand how to instantiate class object, we will have to create a memory for class object to use class properties and their methods for further development work.
AwA = new ;
Here we can see class name “AsicWithAnkit” is instantiated with a created ovject name “AwA”. in second statement we are creating a memory for class object “AwA”. Now we are ready to use class properties using instantiated object. Let’s understand how?
Now when you want to access or use the properties described in the class you can use/access those methods using the objects.
AsicWithAnkit AwA = new ;
AwA.cmd = ‘h2 ;
AwA.addr = ‘h8 ; //Accessing a class properties using object
AwA.display (); //Accessing a class method using object
This way we can access class variables and methods using instantiated objects. System verilog does not require memory allocation and deallocation.
System verilog gives us a different option/way through which we can assign, re-name and copy the objects. Class has many system verilog features and will try to cover those feature in separate follow up blog posts.
ASIC With Ankit
Categories: ASIC FPGA Verification, Object Oriented Programing, System Verilog, Verilog